Positive-pressure blower.



4H. s. LEVY & 9. H. BRANDES.

POSITIVE PRESSURE BLOWER.

APPLICATION FILED NOV. 10, 1910.

Patented Mar. 5,1912. 9

UNITED sTAtrEs PATENT OFFICE.

HOWARD S. LEVY AND GORDON I-I. BRANDES, OF PHILADELPHIA, PENNSYLVANIA.

POSITIVE-PRESSURE BLOWER.

Specification of Letters Patent.

Patented Mar. 5, 1912.

To all whom it may concern:

Be it known that we, HOWARD S. LEVY and GORDON H. BRANDES, both citizens of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Positive-Pressure Blowers, of which the following is a specification.

Our invention appertains to improvements in rotary compressors or positive pressure blowers, the object being to provide a simple, efl'ective and easily constructed blower or compressor for fluids as air or gas, by means of which air or gas is entrapped and is compressed prior to delivery.

A compressor or blower made to accord with our invention includes means whereby air or gas is drawn into a pressure chamber where it is entrapped and is compressed by a diminishing of the size of the chambers, the area of such chambers being diminished until the discharge opening to which the eduction pipe is connected has been passed- In the accompanying drawings, Figure 1 is a side elevation showing one of the cylinder heads removed. Fig. is a front elevation. Fig. 3 is a view similar to Fig. 1 showing a slightly modified form of our improvement. Fig. 4 is a front elevation of the rotary member, partly in section. Fig. 5 is a detail sectional view on the line 5-5, and Figs. 6 and 7 are detail sectional views on a larger scale than the other views.

In the make up of our improved rotary compressor or positive pressure blowers as shown by the accompanying drawings, the casing 1 comprises a cylinder that has a suitable base and flanges for attaching the heads to the casing, which casing has chambers 2 and 3 each chamber communicating with the interior of the cylinder by means of openings through its wall. The angular walls on the exterior of the cylinder that form the chambers 2 and 3 are preferably provided with duplex pipe connections for the purpose of attaching to the walls of the casing induction and eduction pipes, and in practice but one of the connections for each chamber is used the other one being closed by a stopper or plug 4.

The openings or ways 5 and 6 through the wall of the cylinder 1, may be varied as to position, to meet the requirements under which the machine is used, for the degree of compression and the quantity of air ejected and the pressure to which it is subjected may be varied by changmg the distance between the ends of the openings or by increasing or diminishing the length of the open mgs.

The heads 7 and 8 of the cylindrical casing 1 are each provided with centrally located shaft bearings and with lubricating ducts for such bearings, these also present means for lubricating eccentric recesses in the heads of the casing and the movable parts of the blower. The lower portion of the casing or the lower chamber 3, is usually provided with a cock for withdrawing therefrom any surplus of lubricating oil or any condensation that may collect therein. The heads 7 and 8 each have formed therein recesses or guideways 9, which are eccentric to the shaft and encircle the same.

The driven shaft 10 within the casing has fast thereon a frame or spider 11, comprising arms or ribs that carry vanes or blades 12, the faces of the blades being concave and the ends of the frames 11 have recesses located in the hubs to surround within the inner ends of the blades the shaft 10, to provide a space which allows the air to circu late bet-ween the spaces formed by the blades and the pistons. The sides of the vanes or blades 12 impinge against the inner walls of the heads 7 and 8 and the outer ends that engage the inner wall of the casing have formed adjacent to saidends offsets 13, in which are formed sockets which constitute parts of knuckle joints, partially circular enlargements on the ends of the pistons 14 being seated in such sockets. The vanes or blades 12 and the frame 11 including the hubs through which the drive shaft passes may be formed in one piece, or the blades may be attached to the arms that form a part of the frame.

The inner ends of the pistons 14: which are hinged to the vanes or blades 12, have lugs or extensions 15 for rollers 16 which enter the eccentric recess 9, to engage the walls thereof; and when the shaft 10 and the frame attached thereto is rotated, in the direction indicated by the arrow, the pistons 14 will be drawn by the blades 12 and will be caused to move toward and away from the inner wall of the cylinder during the rotation of the shaft.

The hubs of the frame 11, at their ends adjacent to the heads of the cylinder and about the shaft have recesses 17, which provides means whereby air may pass from one i of the chambers to the adjacent one, the chambers being formed by the convex faces of the blades 12, the concave faces of the pistons 1a and the concave face of the adjacent blade and in these communicating chambers the air is at normal or atmospheric pressure.

As illustrated the interior of the casing may be considered as comprising sections A, B, C and D, the section A including the induction chamber 3, and the opening therefrom through the cylinder or casing.

B is the compression section, C the eduction section and I) the section in which a vacuum is produced when the pistons therein are moved from a position nearly parallel to the wall of the cylinder toward the shaft.

When a high pressure machine is desired the first portion ofthe port or opening through which the air or gas is supplied, is moved or located nearer the lower end portion of the education port, and by changing the position of the ports the number of effective compression chambers may be increased or diminished.

In a device of the character set forth, the pistons have a positive movement toward the periphery of the cylinder, and in operation we secure in addition to the pressure obtained by positively blowing the air or gas a compression of such fluid within the chambers, due to a gradual decrease in the size of the chambers before the outlet is reached and the degree of the pressure may be regulated in different blowers or compressors by changing the relative positions of the ports. In practice the farther apart, in the direction of the rotation of the shaft, that these openings are the greater will be the compression before the outlet port is reached.

It will be noted that the construction and location of the eccentric recess 9 is such that said recess is never a part of the chambers in which the compression of the air or gas takes place, and that in a blower or compressor of the character shown that there is an entire absence of valves, and that the only external openings are the inlet and outlet ports.

We have shown means for lubricating the bearings for the shaft as well as means for lubricating the eccentric recesses and any surplus oil will find its way to the lower portion of the casing where it may be drawn off through the pet-cock 18.

The construction shown provides a rotary compressor or blower wherein the groove in which the slides or rollers attached to the vanes move is never a part of the chamber or chambers in which the air is compressed, and this particular feature of construction avoids the use of packing or valves, either upon the slides or in the groove.

In Fig. 1, it will be noted that air or fluid is admitted by way of the pipe as indicated by the arrow to the chamber at the upper portion of the casing, and in Fig. 3 into the lower opening and chamber. By the former construction with the outlet at the bottom the vanes are at the lowest point of their path when discharging. The centrifugal force plus the weight of the vanes tends to throw the vanes outward which is balanced by the air cushion acting toward the center, under certain conditions the air cushion may not be strong enough, particularly if the blower or compressor is run at high speed, to entirely counter balance the outward throw and thus cause the shoes or slides to wear, undue wearing permitting the vanes to strike the case and make noise. Such objections may be avoided by the arrangement shown by Fig. 3, which consists in turning the heads of the casing to change the position of the eccentric ways 9, so that they will have the major portion above the center and by changing the outlet to the top, by such change the weight of the vanes acts with the air pressure against the centrifugal force and takes the wear off the outer circumference of the shoes and decreases the liability of noise.

The device herein shown and described provides a rotary compressor or positive pressure blower which in operation provides for the distribution of air, gas or other fluid from a series of compression chambers without appreciable pulsations and with any desired amount of compression. The compressor being particularly adapted for use in connection with gas furnace work, fuel oil plants, glass blowing, sand blasting, acid blast etching, pneumatic service, agitating liquids and for other purposes where the air is taken from a storage tank into which it has been compressed by the blower.

The device is also usable for connections where the work to be performed is at the intake, as is the case of all services Where the production of a more or less complete vacuum is desirable, as differentiated from service where the work to be performed is at the outlet, as partially hereinbefore described.

WVe claim:

1. In a rotary positive pressure blower, a casing having on opposite sides induction and eduction chambers, heads for the casing having centrally located shaft bearings and eccentric guideways, a shaft maintained by the bearings, a frame fixedly attached to the shaft and comprising curved arms and blades, curved pistons pivoted to the blades, extensions on the pistons which carry extensions for engagement with the guideways, the parts being organized to provide intercommunicating spaces adjacent to the shaft and between the blades and pistons and noncommunicating spaces between the casing the blades and the pistons.

2. In a rotary compressor or positive pressure blower, a casing having a cylindrical inner portion provided with induction and eduction chambers located on opposite sides of a line drawn through the center of the casing, heads for the cylinder having centrally located shaft bearings, and guideways positioned to be eccentric to the shaft bearings, a shaft mounted in the bearings, a frame carried by the shaft and provided with radial blades having concave faces, pistons connected to the ends of the blades and means for connecting the pistons with the guideways so that the ends of the pistons will be moved over the concave faces of adjacent blades providing compression chambers the area of which decreases from the induction to the eduotion ports, and means for maintaining communication between each of the areas that include the blades, pistons and shaft.

3. In a rotary compressor or positive pressure blower, a casing having a cylindrical inner portion, chambers on opposite sides of the casing, heads for the casing having centrally located shaft bearings and guideways which are eccentric to the bearings, a shaft having fast thereon a plurality of longitudinally curved blades, pistons hinged to each of the outer ends of the blades the opposite ends of the pistons being adapted to contact with the concave faces of the adjacent blades, means carried by the pistons for engagement with the guideways and means for permitting a circulation of air between the areas comprising the concave faces of the pistons the convex faces of the blades and a portion of the concave face of an adjacent blade, substantially as set forth.

In testimony whereof we afiix our signatures in presence of two witnesses.

HOWARD S. LEVY. GORDON H. BRANDES. Witnesses:

ANsoN B. EVANS, CHARLES K. JoHNsoN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

